Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Bacteriol. 1996 Feb;178(4):1178-86.

Identification of a membrane protein involved in activation of the KinB pathway to sporulation in Bacillus subtilis.

Author information

  • 1Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92037, USA.

Abstract

The initiation of sporulation in Bacillus subtilis is dependent on the phosphorylation of the Spo0A transcription factor mediated by the phosphorelay and by two major kinases, KinA and KinB. Temporal expression of these kinases was analyzed, and an assessment of their respective contributions to the production of Spo0A-P was undertaken. The results show that KinB is expressed and activated prior to KinA; i.e., the two kinases are solicited sequentially in the sporulation process and are thought to be activated by different signaling pathways. A strategy was developed to isolate mutations specifically affecting the KinB pathway, using the newly improved mini-Tn10 delivery vector pIC333. Several mutants were obtained, one of which carried a transposon in a gene coding for a small integral membrane protein, named KbaA. Inactivation of the kbaA gene appeared to affect KinB activity but not transcription of kinB. A Spo+ suppressor (kinB45) of the kbaA null mutation was isolated in the promoter region of kinB. An eightfold increase of kinB expression levels over wild-type levels was observed in the kinB45 mutant. Thus, overexpression of the kinB-kapB operon was sufficient to overcome the sporulation defect caused by inactivation of kbaA in a KinA- strain. Transcription of kinB was found to be repressed by SinR, while the kinB45 mutant was no longer sensitive to SinR regulation. Implications of these observations on the transcriptional regulation of kinB and the role of KbaA in KinB activation are discussed.

PMID:
8576055
[PubMed - indexed for MEDLINE]
PMCID:
PMC177782
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk